Rex Signum
Rex Signum (宝具の原王 (レックス・シグナム), Rekkusu Shigunamu; Latin for "King's Symbol" and Japanese for "Precious Tools of the Original Kings") are ethereal weapons uniquely located within the , and a select few being even further hidden away in the Soul Society West Branch. The weapons are similar to, yet distinct, from Zanpakutō, being spiritual weapons which house souls and grant abilities to those who wield them — the similarities, however, stop here, as the Rex Signum branch off into their own distinct line from this point forward. Legendary artifacts associated with mythology are more than likely a Rex Signum having been glimpsed by mortal eyes. The most well known is perhaps the , the Rex Signum wielded by the legendary . Excalibur would go on to become so well known that is gained a separate classification and distinction even among the Rex Signum: the Verus Rex (王の中の王 (ヴェルス・レックス), Vuerusu Rekkusu; Latin for "True King" and Japanese for "King of Kings"). Those who wield Rex Signum are stated to have the qualities of kings. Attributes The Rex Signum are items, almost exclusively weaponry, without any unique abilities unto themselves. They are, however, quasi-sentient instruments, and while they cannot communicate with their wielder, a Rex Signum always chooses someone who fits its properties. This is due to the fact that a Rex Signum is an item bequeathed with a portion of the soul of a former monarch — a king, queen, or other some such sovereign — who has ruled over what is now known as the United Kingdom of Great Britain and Northern Ireland. This soul fragment only responds to a soul of a similar strength of will, thus the weapon or instrument that the soul resides in will respond to that person and that person only from the moment it is claimed until the moment the wielder passes. Despite the Rex Signum not having any unique abilities, they do each possess a single, solitary strength: Power Enhancement and Cultivation. Whether or not an individual realises it, all Humans are born with the ability to develop unique strengths. Those who do are referred to as Psysis (魂の (プシシズ), Saishizu; originating from the Greek, ti̱s psychí̱s, meaning "of the soul, spiritual"), or otherwise "High-Spec Humans". Whatever the term used, the result is the same. Psysis are humans who have developed a supernatural ability — be it as simple as spiritual awareness, or a more complex ability like those displayed in Fullbringers — and where the Rex Signum displays its strength is the fact that it can trigger, cultivate, and draw out the abilities of Humans. The principle is seemingly the same as the one used by the Quincy, . The soul within the instrument, the Rex Signum, responds to the similar soul that it has chosen; two souls do what one could not, and strength within the wielder bubbles forth, resulting in the awakening of their hidden talents. The end result is always different for each Rex Signum wielder, and as such, no two wielders of the same Rex Signum in history have ever had an ability that are completely the same. Rex Signum are not limited to simply Humans; Souls are capable of wielding them as well, and this extends to Souls such as , should they be so chosen. In the case of a Shinigami wielder being chosen by a Rex Signum, the ability they develop will be separate and distinct from that of their Zanpakutō, though superficial similarities may remain. For any other Soul, the result would be the same as if a Human was chosen. The amount of Rex Signum within the United Kingdom and the Soul Society West Branch have not been properly documented, but are said to number in the same amount as the monarchs themselves. Evolution The Rex Signum expresses its power through the one who wields it in two ways, and these are referred to as stages. The first stage is referred to as Channeling (チャネリング (個性の流れ), Chaneringu; lit. "Personality Flow"). This stage is the simplest method in which the Rex Signum is utilised, and it begins with the very manifestation of the individuals unique ability, and the form of their Rex Signum. The Channeling stage is reached when a Rex Signum first chooses a wielder, and it adjusts its shape to match the user's latent — or present, in the case of a wielder who is already a Psysis — ability. It is in the Channeling stage that a user gains experience with the Rex Signum, and grows with their weapon. As the soul of the former monarch within the weapon becomes more attuned to the soul of its chosen wielder, the Rex Signum reaches the Raiment (ライメント (個性の佩用), Raimento; lit. "Personality Wearing") stage of use. The Raiment stage manifests the abilities of the Psysis wielding the Rex Signum to its fullest. While the weapon itself does not change, the user gains attire composed entirely of spiritual energy that suits their personality, as well as granting them a degree of protection due to the sheer density of the spiritual energy used to create the attitire. The raiment in this stage is also referred to as the Robe of Kings (ローブ·オーブ·キングズ (国主の武装); Rōbu obu Kinguzu; lit. "Sovereign's Armament"). The change is not merely visual, however; the Raiment stage unlocks abilities that the user would otherwise have been unable to use in the Channeling stage, and their overall paremeters — strength, speed, durability, spiritual energy — vastly increase. Drawbacks Humans and Souls who do not fit the criteria of the Rex Signum are able to wield it. In some cases, such as the legendary Excalibur, the Rex Signum will refuse to move for anyone except the one it chooses. In other cases, the instrument maintains whatever form it has, but will neither transform nor showcase any spiritual abilities for the one who attempts to pick it up. In the worst case scenario, the soul within the Rex Signum will attempt to kill someone who does not meet their criteria. There are, however, individuals who cannot use a Rex Signum regardless of circumstance. The first of these are Arrancar and Hollows, who are rejected by all the Rex Signum, and cannot be chosen as wielders. This is due to the fact that the Rex Signum themselves are particularly lethal to Hollows, purifying them in the manner akin to a Zanpakutō. This weakness applies even to Soul-Hollow hybrids, though exceptions can be made in rare cases, as the Rex Signum's monarch may see it fit to ally with one that uses Hollow powers. The second of these are Quincy who possess a Schrift, and this is due to the simple fact that Yhwach's soul already dwells within their body. The soul of the former monarch within the Rex Signum cannot coexist with a fellow soul that not only fulfills the exact same purpose, but surpasses their own in strength of will. A Quincy who attempts to wield a Rex Signum will be rejected quickly out of the soul's fear of being overwhelmed and consumed by Yhwach. Trivia *The bare premise of the weaponry, royal weapons in whom dwell the souls of kings, and can be wielded only by the chosen, is based loosely on the Ring of the Lucii and the Royal Arms from Final Fantasy XV.